1. Field of the Invention
The present invention relates to a track roller bearing with stud and an lubrication plug used in the track roller bearing with stud which smoothly guide a linear motion or the like in a machine tool, an industrial robot, and the like, and which is most commonly use as a cam follower.
2. Description of the Prior Art
FIG. 1 is an example of a track roller bearing with stud of the prior art.
The track roller bearing with stud comprises a stud 1, an outer ring 2, a side plate 3, a plurality of rollers 4, and a cage 6.
The stud 1 is arranged like an axis, and has a flange 1a, a track surface 1b as a track portion, a side plate insertion portion 1c, an attachment portion 1d, and a threaded portion 1e formed in order from an end surface.
The outer ring 2 has one end portion which is prevented from slipping off in the axial direction by the flange 1a, and is larger than the outside diameter of the flange 1a and is formed like a thick-waled ring, and has a track surface 2b formed on the inner circumference corresponding to the track surface 1b, and is rotatably inserted onto the stud 1.
The plurality of rollers 4 are juxtaposed between the track surface 1b and track surface 2b as rolling elements.
The cage 6 is located between the track surface 1b and track surface 2b so as to retain the plurality of rollers 4 with some spaces.
The side plate 3 is located at the other end portion of the outer ring 2 opposite to the flange 1a, and is formed like a doughnut-plate with an outside diameter approximately equal to the flange 1a, and an inside diameter portion thereof is inserted onto the side plate insertion portion 1c of the stud 1 so as to prevent the outer ring 2, the plurality of rollers 4, and the cage 6 from slipping off in the axial direction, together with the flange 1a.
In the track roller bearing with stud, usually, the outer ring 2 rotates relative to the stud 1.
The stud 1 has a lubricant supply hole 1g approximately through the whole length centered at the axis, and lubrication hole 1h and lubrication hole 1i are opened, which are respectively connected to the track surface 1b and the attachment portion 1g from the supply hole 1g. The supply hole 1g and the lubrication hole 1h and lubrication hole 1i form a lubricating passage for a lubricant. Then, in an end surface of the threaded portion 1e side of the stud 1, a lubricant filler port 1n as a lubricat filler inlet for the lubricant connected to the lubricating passage is formed, and at the lubricant filler port 1n, a grease nipple 15 as a lubricating device is provided.
Furthermore, as shown in FIG. 1 and FIG. 2, in the stud 1, a hexagon socket 1r is formed in an end surface on the flange 1a side. The hexagon socket 1r is formed so that when attaching or removing the track roller bearing with stud, a fastening tool such as a hexagonal wrench may be inserted into the hexagon socket 1r for turning the stud 1.
FIG. 3 shows a common example in service of the track roller bearing with stud.
The track roller bearing with stud is inserted into a housing 8 of a frame equipped on a machine tool or the like, and onto the threaded portion 1e of the stud 1 projecting on the opposite side of the housing 8 of this frame, a nut 11 is screwed through a spring washer 10, and they are fastened and fixed by turning the nut 11 with a wrench or the like, or by turning the stud 1 after engaging a fastening tool such as a hexagonal wrench into the hexagon socket 1r.
Usually, the outside diameter surface of the outer ring 2 slidingly touches the track 13 formed by a track of a straight passage or a track of a cam mechanism, and the outer ring 2 turns and a relative motion to the track 13 is performed.
In the attachment state in FIG. 3, usually, when a grease lubrication is performed, the grease as a lubricant is properly fed to the grease nipple 15 as a lubricating device by a grease gun or the like so as to be filled in the lubricating passage, and is supplied through the lubrication hole 1h to each of the track surface 1b and track surface 2b of the stud 1 and the outer ring 2, and the rollers 4.
For example, in a manufacturing device or the like related to semiconductors, lots of small sized track roller bearing with studs with a nominal diameter of not more than approximately 6 mm, are installed.
In the small sized track roller bearing with stud, there is no space to form a lubricant filler port 1n in an end surface of the threaded portion 1e of the stud 1, and the grease nipple as a lubricating device cannot be arranged and the lubrication feed cannot be performed. Therefore, the lubrication is performed only by the grease as a lubricant first sealed into the track surface.
Accordingly, the replacement of the track roller bearing with stud is performed by disassembling the device before the filled lubricant has been consumed, which takes a lot of time and lab or.